feat: add resource management types and utilities for memory optimization

- Add Disposable, BufferConfig, MemoryMetrics, CleanupRegistration types
- Create src/config/buffer-limits.ts with consolidated buffer size constants
- Create src/config/map-limits.ts with Map size limits to prevent unbounded growth
- Implement BufferAccumulator utility with configurable trim and onTrim callback
- Implement LRUMap with automatic eviction and O(1) operations
- Implement CleanupManager for unified resource cleanup with isStopped guard
- Add comprehensive tests for all new utilities

This lays the foundation for memory leak prevention and performance improvements.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/types.ts

@@ -11,6 +11,77 @@
  * - Inner loop tracking (Ralph Wiggum detection)
  */
 
+// ========== Resource Management Types ==========
+
+/**
+ * Interface for objects that hold resources requiring explicit cleanup.
+ * Implementing classes should release timers, watchers, and other resources in dispose().
+ */
+export interface Disposable {
+  /** Release all held resources. Safe to call multiple times. */
+  dispose(): void;
+  /** Whether this object has been disposed */
+  readonly isDisposed: boolean;
+}
+
+/**
+ * Configuration for buffer accumulator instances.
+ * Used for terminal buffers, text output, and other size-limited string storage.
+ */
+export interface BufferConfig {
+  /** Maximum buffer size in bytes before trimming */
+  maxSize: number;
+  /** Size to trim to when maxSize is exceeded */
+  trimSize: number;
+  /** Optional callback invoked when buffer is trimmed */
+  onTrim?: (trimmedBytes: number) => void;
+}
+
+/**
+ * Memory metrics for monitoring and debugging.
+ * Extends Node.js process.memoryUsage() with application-specific tracking.
+ */
+export interface MemoryMetrics {
+  /** Heap memory used by V8 (bytes) */
+  heapUsed: number;
+  /** Total heap size allocated by V8 (bytes) */
+  heapTotal: number;
+  /** Memory used by C++ objects bound to JavaScript (bytes) */
+  external: number;
+  /** Memory used by ArrayBuffers and SharedArrayBuffers (bytes) */
+  arrayBuffers: number;
+  /** Sizes of tracked Maps by name */
+  mapSizes: Record<string, number>;
+  /** Number of active timers (setTimeout/setInterval) */
+  timerCount: number;
+  /** Number of active file system watchers */
+  watcherCount: number;
+  /** Timestamp when metrics were collected */
+  timestamp: number;
+}
+
+/**
+ * Resource types that can be registered for cleanup.
+ */
+export type CleanupResourceType = 'timer' | 'interval' | 'watcher' | 'listener' | 'stream';
+
+/**
+ * Registration entry for a cleanup resource.
+ * Used by CleanupManager to track and dispose resources.
+ */
+export interface CleanupRegistration {
+  /** Unique identifier for this registration */
+  id: string;
+  /** Type of resource */
+  type: CleanupResourceType;
+  /** Human-readable description for debugging */
+  description: string;
+  /** Cleanup function to call on dispose */
+  cleanup: () => void;
+  /** Timestamp when registered */
+  registeredAt: number;
+}
+
 // ========== Core Status Types ==========
 
 /** Status of a Claude session */